1. Field of the Invention
The invention relates to a technique for function parameter setting, and particularly relates to a method with function parameter setting and an integrated circuit using the same.
2. Description of Related Art
When an integrated circuit (IC) is activated, the hardware connected to a function pin of the IC is generally used to obtain an initial setting value. For example, in a commonly used voltage-dividing setting method, at least two resistors are used to set the initial setting value in a voltage-dividing manner. The IC detects a percentage of a divided voltage through the function pin, so as to obtain the setting value.
Another conventional technique is a parallel resistance setting method, and in the parallel resistance setting method, a constant detecting current flows to or flows out from the function pin to form a voltage detecting value at the function pin, so as to detect setting intervals of parallel resistance values. A detection accuracy of the voltage-dividing setting method on the setting intervals is generally higher than that of the parallel resistance setting method. However, if the parallel resistance setting method is used for detecting the resistance value setting intervals, some resistance value setting intervals for the voltage-dividing setting method are sacrificed. If the two setting methods are used in the conventional technique, some resistance value setting intervals have to be sacrificed.
Moreover, the detecting current used in the parallel resistance setting method is confined within a specific range, and a comparator adopted for the detection also has a corresponding deviation value and other design error factors. Considering a design security, the greater the parallel resistance value of the setting interval is, the larger difference of the parallel resistance setting values of the two adjacent setting intervals is. Therefore, a range of the setting interval that can be used by the parallel resistance setting method of the convention technique is limited.
Moreover, a special example of a degradation circuit in the parallel resistance setting method is that the function pin is connected to one end of a resistor, and another end of the resistor is connected to the ground or a power supply.